Method and apparatus for draining condensate from a gas water heater exhaust system

ABSTRACT

A method and apparatus for conveying condensate from an exhaust system of a gas water heater to a drain. The method includes the steps of operating the gas water heater to produce products of combustion, operating a blower to cause the products of combustion to flow through the exhaust system to atmosphere, allowing condensate from the products of combustion to form within the exhaust system, using a drain conduit to connect a relatively high pressure zone of the exhaust system to a relatively low pressure zone of the exhaust system, using a pressure differential between the relatively high pressure zone and the relatively low pressure zone to convey condensate through the drain conduit from the relatively high pressure zone to the relatively low pressure zone, and conveying condensate from the relatively low pressure zone to the drain.

RELATED APPLICATIONS

This application claims priority to co-pending U.S. Provisional PatentApplication No. 61/407,778 filed on Oct. 28, 2010, the entire content ofwhich is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to gas water heaters, and moreparticularly to gas water heaters including exhaust systems.

SUMMARY OF THE INVENTION

The present invention provides, in one aspect, a method of conveyingcondensate from an exhaust system of a gas water heater to a drain. Themethod includes the steps of operating the gas water heater to produceproducts of combustion, connecting an exhaust outlet of the gas waterheater to the exhaust system such that the exhaust system receives theproducts of combustion, operating a blower to cause the products ofcombustion to flow through the exhaust system to atmosphere, allowingcondensate from the products of combustion to form within the exhaustsystem, using a drain conduit to connect a relatively high pressure zoneof the exhaust system to a relatively low pressure zone of the exhaustsystem, the relatively low pressure zone between the exhaust outlet andthe blower and the relatively high pressure zone downstream of therelatively low pressure zone, using a pressure differential between therelatively high pressure zone and the relatively low pressure zone toconvey condensate through the drain conduit from the relatively highpressure zone to the relatively low pressure zone, and conveyingcondensate from the relatively low pressure zone to the drain.

The present invention provides, in another aspect, a gas water heaterincluding a storage tank for storing water, a combustion chamber, aburner positioned in the combustion chamber, the burner for producingproducts of combustion, a heat exchanger positioned in the storage tankfor receiving the products of combustion from the combustion chamber andfor transferring heat from the products of combustion to the waterstored in the storage tank, the heat exchanger including an outlet thatextends from the storage tank, and an exhaust system. The exhaust systemincludes a first exhaust conduit connected to the outlet to receive theproducts of combustion from the heat exchanger, a second exhaust conduitfluidly connected to atmosphere, a blower connected between the firstexhaust conduit and the second exhaust conduit with the first exhaustconduit upstream of the blower and the second exhaust conduit downstreamof the blower, a first drain fitting in the first exhaust conduitbetween the outlet and the blower and a second drain fitting downstreamof the first drain fitting such that the first drain fitting is at afirst pressure and the second drain fitting is at second pressure, thesecond pressure greater than the first pressure, and a drain conduitconnected between the first drain fitting and the second drain fittingsuch that the difference between the second pressure and the firstpressure causes condensate from the products of combustion to flowthrough the drain conduit from the second drain fitting to the firstdrain fitting.

Other features and aspects of the invention will become apparent byconsideration of the following detailed description and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a gas water heater.

FIG. 2 is a perspective view of the gas water heater of FIG. 1 includinga gravity-based condensate drainage system.

FIG. 3 is a schematic view of the gas water heater of FIG. 1 including agravity-based condensate drainage system

FIG. 4 is a perspective view of the gas water heater of FIG. 1 includinga pressure-based condensate drainage system.

FIG. 5 is a schematic view of the gas water heater of FIG. 1 including apressure-based condensate drainage system.

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways. Also, it is to be understood thatthe phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting.

DETAILED DESCRIPTION

FIG. 1 illustrates a gas water heater 100 including a storage tank 105,an outer case 110, a cold water inlet 115, a hot water outlet 120, acombustion chamber 125, a burner 130, and a flue or heat exchanger 135.The water heater 100 may also include additional conventional componentsof a gas-fired storage water heater, for example, a gas valve, atemperature and pressure (T&P) valve, a sacrificial anode, and a drainvalve. The storage tank 105 is surrounded by the outer case 110. Thecold water inlet 115 delivers cold water to the storage tank 105 and thehot water outlet 120 delivers hot water to an end-use location, forexample, a faucet. The burner 130 is positioned in the combustionchamber 125 and combusts a fuel/air mixture to create products ofcombustion. The products of combustion flow from the combustion chamber125 to the heat exchanger 135. As the products of combustion travelthrough the heat exchanger 135, heat is transferred from the products ofcombustion to the water stored in the storage tank 105. The heatexchanger 135 includes an outlet 140 that extends from the storage tank105 through the outer case 110.

FIGS. 2-3 illustrate an exhaust system 145 that conveys the products ofcombustion from the outlet 140 of the heat exchanger 135 to atmosphere.The exhaust system 145 includes a blower 150, an exhaust conduit 155upstream of the blower 150, and an exhaust conduit 160 downstream of theblower 150. A vent attenuation assembly 165 in the exhaust conduit 160is optional. The exhaust conduit 155 connects the outlet 140 to theblower 150. The exhaust conduit 155 extends vertically along the side ofthe water heater 100 and is spaced apart from the storage tank 105 andthe outer case 100. The exhaust conduit 160 connects the blower 150 toan exhaust vent (not shown). The vent attenuation assembly 165 ispositioned between the blower 150 and the exhaust vent to reduce fannoise created by the blower 150. When the water heater 100 and theblower 150 are operating, the products of combustion travel from theoutlet 140 through the exhaust conduit 155, through the blower 150, andthrough the exhaust conduit 160 and vent attenuation assembly 165 to theexhaust vent to be vented to the atmosphere outside of the buildingcontaining the water heater 100, as shown by the dashed arrows in FIG.3.

As the products of combustion cool in the exhaust system 145, condensateis formed. The condensate must be drained from the exhaust system 145. Aconventional method of draining the condensate is to use gravity todrain condensate from several locations in the exhaust system 145. Theblower 150 includes drain fittings 170 and 175. The drain fitting 170 isin the housing of the blower 150 and the drain fitting 175 is in theoutlet portion of the blower 150. The vent attenuation assembly 165includes a drain fitting 180. A drain hose or conduit 185 is connectedto each drain fitting 170, 175, and 180. The exhaust conduit 155includes a lower portion with a trap 190. The trap 190 is u-shaped andis positioned below the outlet 140 of the heat exchanger 135. A maindrain conduit 195 is connected to the trap 190 and runs to a suitabledrain 200. All of the drain conduits 185 are in fluid communication withthe main drain conduit 195. The drain conduits 185 from the drainfittings 170 and 175 are connected to one another by a tee 205 and thento the main drain conduit 195 by an intermediate conduit 208 and anothertee 205. The drain conduit 185 from the drain fitting 180 is connectedto the main drain conduit 195 by a tee 205. Each of the drain conduits185 includes a trap loop 210 located upstream of any tee 205 connectedto that drain conduit 185. As condensate forms in the exhaust system145, the condensate is drawn by gravity towards one of the drainfittings 170, 175, and 180. From each drain fitting 170, 175, and 180,the condensate is drawn by gravity through a corresponding drain conduit185 to the main drain conduit 195 and through the main drain conduit 195to the drain 200, as shown by the solid arrows in FIG. 3. Alternatively,each of the drain conduits 185 and the main drain conduit 195 areindividually routed to the drain 200.

The drawbacks of the gravity-based condensate drainage system as shownin FIGS. 2-3 include installation, appearance, setup, and function. Forinstallation, the installer can be confused about how to connect androute the drain conduits 185, even when provided with instructions. Forappearance, the multiple drain conduits 185 and loops 210 outside of thewater heater 100 and exhaust system 145 can look messy. For setup, eachindividual drain conduit 185 has to be primed and each individual loop210 must be formed and positioned correctly. For function, gravity doesnot ensure complete drainage of the condensate from the exhaust system145, which causes nuisances in the field. When the blower 150 isoperating, the exhaust conduit 155 is at a first pressure P1, thehousing of the blower 150 including drain fitting 170 is at a secondpressure P2, the outlet portion of the blower 150 including drainfitting 175 is at a third pressure P3, and the vent attenuation assembly165 including drain fitting 180 is at a fourth pressure P4. PressuresP1, P2, P3, and P4 all are lower than the ambient pressure at the drain200, which causes the drain conduits 185 to not drain well because thepressure differentials between the pressures P1, P2, P3, and P4 andambient pressure work against the effect of gravity on the condensate inthe drain conduits 185. Furthermore, as shown in FIG. 3, any rise 215 ina drain conduit 185 upstream of a loop 210 traps condensate and airupstream of the loop 210, thereby inhibiting the flow of condensatethrough the loop 210 and drain conduit 185.

FIGS. 4-5 illustrate the gas fueled water heater 100 and an exhaustsystem 245 similar to the exhaust system 145 shown in FIGS. 2-3. Thecomponents of the exhaust system 245 similar to those described withrespect to exhaust system 145 are numbered with the same referencenumeral plus one-hundred. The exhaust system 245 uses a pressure-basedcondensate drainage system that overcomes the drawbacks of agravity-based drainage system as shown in FIGS. 2-3.

The exhaust conduit 255 includes an adaptor 320 positioned near the topof the water heater 100. The adaptor 320 includes multiple drainfittings 325. At a minimum, the adaptor 320 includes one drain fitting325. The adaptor 320 and the drain fittings 325 are located on avertical portion 327 of the exhaust conduit 255. The drain fittings 325are located adjacent to the top of the water heater 100 and the top ofthe storage tank 110. The drain fittings 325 can be poka-yoke orerror-proofed fittings which require the installer to remove a plug orother component for each fitting before attaching a drain conduit 285.This prevents a drain fitting 325 from being left open if the installerdoes not install the same number of drain conduits 285 as the number ofdrain fittings 325 provided by the adaptor 320. In the event a drainfitting 325 is left open and the water heater 100 and the blower 250 areoperating, the adaptor 320 will be at a negative pressure relative toatmosphere such that products of combustion will not escape through theopen drain fitting 325. Preferably, the drain fittings 325 are barbfittings.

Drain fittings 270, 275, and 280 are located downstream of the adaptor320. More or fewer drain fittings downstream of the adaptor 320 can beincluded in the exhaust system 245. For example, as shown in FIG. 4, theblower 250 includes a third drain fitting 330. Drain conduits 285 areconnected between the each of the drain fittings 270, 275, 280, and 330and a drain fitting 325 of the adaptor 320. The adaptor 320 ispositioned below all of the downstream drain fittings 270, 275, 280, and330.

As shown in FIG. 5, when the blower 250 is operating, the exhaustconduit 255 including drain fittings 325 is at a first pressure P1, theinlet of blower 250 including drain fitting 270 is at a second pressureP2, the outlet of the blower 250 including drain fitting 275 is at athird pressure P3, and the vent attenuation assembly 265 including drainfitting 280 is at a fourth pressure P4. The blower 250 runs when thewater heater 100 is operating to create products of combustion. Theblower 250 may also run before and/or after the water heater 100 isoperating to produce products of combustion. The second pressure P2, thethird pressure P3, and the fourth pressure P4 are all greater than thefirst pressure P1. For example, the second pressure P2 and the firstpressure P1 are both negative relative to atmosphere with the firstpressure P1 being more negative than the second pressure P2, so thesecond pressure P2 is considered greater than or higher than the firstpressure P1 relative to atmosphere.

Each of the drain fittings 270, 275, 280, and 330 is located in arelatively high pressure zone when compared to a relatively low pressurezone in which the drain fittings 325 are located. The relatively highpressure zones are located downstream of the relatively low pressurezone in which the drain fittings 325 are located. The pressuredifferentials between the second pressure P2 and the first pressure P1,the third pressure P3 and the first pressure P1, and the fourth pressureP4 and the first pressure P1 drive the condensate from the relativelyhigh pressure zones through a corresponding drain conduit 285 to therelatively low pressure zone in the exhaust conduit 255. Gravityfunctions as a subsidiary method of drainage through the drain conduits285 because the drain fittings 325 of the adaptor 320 are positionedlower than all of the drain fittings 270, 275, 280, and 330.

Gravity causes the condensate to travel downward through the exhaustconduit 255 from the drain fittings 325 to the trap 290. Condensatecollects in the trap 290 until the collected condensate reaches theelevation of the main drainage conduit 295, which delivers thecondensate to the drain 200.

The pressure-based condensate drainage system shown in FIGS. 4-5improves on the installation, appearance, setup, and function of thegravity-based condensate drainage system shown in FIGS. 2-3. Thepressure-based condensate drainage system is easier to install, neaterlooking, and requires less time to set up than the gravity-basedcondensate drainage system. For example, there is no need to prime thedrain conduits 285 of the pressure-based condensate drainage system,only the main drain conduit 295 needs priming. Additionally, thecondensate-based drainage system drains condensate more reliably andfunctions better than the gravity-based condensate drainage system.

Various features of the invention are set forth in the following claims.

1. A method of conveying condensate from an exhaust system of a gaswater heater to a drain, the method comprising: operating the gas waterheater to produce products of combustion; connecting an exhaust outletof the gas water heater to the exhaust system such that the exhaustsystem receives the products of combustion; operating a blower to causethe products of combustion to flow through the exhaust system toatmosphere; allowing condensate from the products of combustion to formwithin the exhaust system; using a drain conduit to connect a relativelyhigh pressure zone of the exhaust system to a relatively low pressurezone of the exhaust system, the relatively low pressure zone between theexhaust outlet and the blower and the relatively high pressure zonedownstream of the relatively low pressure zone; using a pressuredifferential between the relatively high pressure zone and therelatively low pressure zone to convey condensate through the drainconduit from the relatively high pressure zone to the relatively lowpressure zone; and conveying condensate from the relatively low pressurezone to the drain.
 2. The method of claim 1, wherein the relatively highpressure zone is located at the blower.
 3. The method of claim 1,wherein the relatively high pressure zone is located downstream of theblower.
 4. The method of claim 1, further comprising: conveyingcondensate from the relatively low pressure zone to the drain at leastin part due to gravity.
 5. The method of claim 1, further comprising:using a second drain conduit to connected a second relatively highpressure zone of the exhaust system to the relatively low pressure zone;and using a second pressure differential between the second relativelyhigh pressure zone and the relatively low pressure zone to conveycondensate through the second drain conduit from the second relativelyhigh pressure zone to the relatively low pressure zone.
 6. A gas waterheater comprising: a storage tank for storing water; a combustionchamber; a burner positioned in the combustion chamber, the burner forproducing products of combustion; a heat exchanger positioned in thestorage tank for receiving the products of combustion from thecombustion chamber and for transferring heat from the products ofcombustion to the water stored in the storage tank, the heat exchangerincluding an outlet that extends from the storage tank; and an exhaustsystem including a first exhaust conduit connected to the outlet toreceive the products of combustion from the heat exchanger, a secondexhaust conduit fluidly connected to atmosphere, a blower connectedbetween the first exhaust conduit and the second exhaust conduit withthe first exhaust conduit upstream of the blower and the second exhaustconduit downstream of the blower, a first drain fitting in the firstexhaust conduit between the outlet and the blower and a second drainfitting downstream of the first drain fitting such that the first drainfitting is at a first pressure and the second drain fitting is at secondpressure, the second pressure greater than the first pressure, and adrain conduit connected between the first drain fitting and the seconddrain fitting such that the difference between the second pressure andthe first pressure causes condensate from the products of combustion toflow through the drain conduit from the second drain fitting to thefirst drain fitting.
 7. The gas water heater of claim 6 wherein thefirst exhaust conduit further includes a vertical portion and the firstdrain fitting is located on the vertical portion.
 8. The gas waterheater of claim 7 wherein the first drain fitting is located adjacent tothe top of the storage tank.
 9. The gas water heater of claim 8 whereinthe blower includes the second drain fitting.
 10. The gas water heaterof claim 9, wherein the blower is located above the storage tank. 11.The gas water heater of claim 10, further comprising: a trap connectedto the first exhaust conduit and positioned below the outlet of the heatexchanger; and a second drain conduit connected to the trap, the seconddrain conduit for conveying condensate to a drain.
 12. The gas waterheater of claim 8 wherein the second drain fitting is located downstreamof the blower.
 13. The gas water heater of claim 12, wherein the bloweris located above the storage tank.
 14. The gas water heater of claim 13,further comprising: a trap connected to the first exhaust conduit andpositioned below the outlet of the heat exchanger; and a second drainconduit connected to the trap, the second drain conduit for conveyingcondensate to a drain.
 15. The gas water heater of claim 6 wherein theblower includes the second drain fitting.
 16. The gas water heater ofclaim 15, wherein the blower is located above the storage tank.
 17. Thegas water heater of claim 6 wherein the second drain fitting is locateddownstream of the blower.
 18. The gas water heater of claim 17, whereinthe blower is located above the storage tank.
 19. The gas water heaterof claim 7, wherein the blower is located above the storage tank. 20.The gas water heater of claim 7, further comprising: a trap connected tothe first exhaust conduit and positioned below the outlet of the heatexchanger; and a second drain conduit connected to the trap, the seconddrain conduit for conveying condensate to a drain.